Global Pulse developed a real-time social media monitor to measure and explore online discourse about climate change in support of the United Nations Climate Summit in 2014. The publicly accessible monitor analysed tweets in English, Spanish and French on a daily basis to show the volume and content of tweets about climate change across a range of topic areas such as economy and energy. Measuring and visualising public tweets over time created a baseline of engagement, and showed a significant increase in discussions about climate change around the Climate Summit. By providing a tool for comparing interest level between topics and regions, and monitoring the social media impact of climate-related public communications and events, the monitor could be used to measure awareness, support climate policy decision-making and to drive further public engagement.